Understanding Bokeh

“Boke” is the Japanese word for blurriness and is the opposite of “pinto”, the Japanese word for sharpness in a photo. This term was introduced by Mike Johnston in an article for the magazine “Photo Techniques” (March/April 1997 issue). To help the English speaking people pronounce the word “boke” properly, the “h” was added, explaining that it should be pronounced as “boh – kay“.

As mentioned, bokeh is the blurry part of a photo. It is important to understand that this blurred part of the photo is fuzzy, because it is out of focus. If a photo is not sharp due to movement because of a too slow shutter speed (or/and camera shake), then this is not called bokeh. Bokeh is “unsharp” as a result of objects that are outside the depth of field. To truly understand bokeh, one must understand how depth of field (or DoF) and aperture work.

The subject is sharp, the rest of the photo is out of focus. This part is called bokeh.

The DoF is mainly determined by the aperture (and focal length, and the distance from the camera to the subject/object). Choosing a large aperture (small number) combined with a longer lens will result in a narrow depth of field. A narrow DoF means that only a small portion of the photo is in focus. In the image above, a 50mm lens was used (on a crop camera) combined with an aperture of f2.8. The outcome is that only the bumblebee is in focus and the rest is out of focus. If the subject of the photo is far from the camera, the depth of field increases (and the amount of bokeh reduces).

A small aperture of f8 (on a 50mm lens) and a subject in the far distance produces a fairly large depth of field and no visible bokeh.

How to create a nice bokeh?

There are three simple rules that can be applied to create bokeh:

Use a large aperture

Use a focal length longer than 35mm on a crop camera and 50mm on a full frame camera

The subject you are focusing on should be close to the camera, and the background far away.

A large aperture creates the best bokeh. Of course it is dependent on your personal taste, but consider both images below. They are taken with the same lens, but a different aperture. The out of focus lights in the first image, shot with an aperture of f1.4, look better than the bokeh in the picture taken with a smaller aperture of f1.8 (the second photo). The reason is because the DoF is increased by reducing the aperture, hence, more of the aperture blades are shown.

Bokeh with the Nifty Fifty at f1.4 is brilliant!

The 7 aperture blades are clearly visible when the Nikon 50 mm lens is set at f1.8.

The quality of bokeh is influenced by the number of aperture blades and the quality of the glass in a lens. More aperture blades create rounder shapes, which is pleasant to the eye.

A rough sketch of the aperture. On the left side 6 aperture blades, on the right side 9. As visible, more aperture blades create a “rounder” shape.

The softer the transformation from sharp to out of focus, the more pleasing the background blur will be. A long focal length is needed to compress the scene. Using a long focal length and large aperture while moving the background of the image further away will create softer bokeh.

Be aware of your background however. As visible in the image below, the little Christmas lights form a fun playground for bokeh. The light and dark parts of the background form a great contrast, something that can work distracting in a photo too.

Grolsch beer, shot at f1.4. The brand name of this beer is really hard to pronounce for non Dutch speakers!

It is said that the quality of bokeh is better on a full frame camera than on a crop camera. The logic behind this statement, is that a FF-camera has a smaller depth of field with the same aperture settings (read more on that by clicking here).

Nonetheless, whether you have a compact camera, a “mirrorless” camera, or a DSLR, you can always achieve some bokeh by applying the three rules mentioned above. And if your camera by any change does not support manual settings (or you don’t know how they work), set your camera to “macro mode” (usually a flower icon), zoom in, get close to the subject and choose a background in the far distance to reach some form of bokeh.